1. Field of the Invention
This invention relates to an improved reinforced coolant guard for use in oil film bearings of the type employed in rolling mills.
2. Description of the Prior Art
A typical rolling mill oil film bearing with a seal arrangement including a coolant guard is shown in FIG. 1. The roll 10 has an end face 12 joined by an intermediate tapered section 14 to a reduced diameter section 16 surrounded by a sleeve 18. The sleeve is keyed or otherwise secured to the roll neck, and is journalled in a bushing 20 fixed within a chock 22. Oil is supplied continuously between the sleeve and bushing, and a seal assembly generally indicated at 24 surrounds the intermediate tapered section 14 to prevent oil from escaping from the bearing and also to prevent externally applied cooling water and entrained contaminants such as dirt, mill scale, etc. from penetrating into the bearing.
The seal assembly 24 includes a flexible flanged neck seal 26 and a seal inner ring 28, both of which are carried on the roll for rotation therewith, and a seal end plate 30 and coolant guard 34, both of which are fixed in relation to the chock 22. This sealing arrangement is well known to those skilled in the art, and thus little if any further explanation is required, except perhaps with regard to the coolant guard 34.
The coolant guard comprises an elastomeric molded component having a radially extending mounting flange 36 and an integrally associated sealing flange 38. The mounting flange 36 is located in a circular recess 40 in the seal end plate 30, where it is surrounded by a circular shoulder 41. The recess 40 has a flat annular mounting surface 42 against which the mounting flange is secured by means of circumferentially spaced screws 44. When the mounting flange 36 is thus secured, the sealing flange 38 extends angularly into resilient sealing contact with the roll end face 12.
The coolant guard provides the first line of defense against the unwanted and potentially damaging ingress of cooling water and entrained contaminants into the bearing. It also cooperates with the seal inner ring 28 to establish a sealing labyrinth leading to a drain opening (not shown) in the seal end plate. Additionally, when the bearing is being removed from the roll neck, the mounting flange 36 contacts the outermost peripheral flange of the seal inner ring 28 and exerts through it a force sufficient to pull both the inner seal ring and the neck seal 26 off of the roll neck. In order to facilitate this pulling action, the stiffness of the mounting flange is elevated above that of the sealing flange by increasing its durometer hardness. Also, it will be understood that during rolling, the roll neck on the non-thrust side of the roll will have a tendency to shift or "float" axially with regard to the chock 22 due to thermal expansion, mechanical tolerances, etc. If kept within acceptable limits, this axial floating does not damage the bearing. The shoulder 41 serves as a stop against which the roll end face 12 can abut to limit axial floating and thereby safeguard internal bearing components from damage that might otherwise occur.
The coolant guard 34 is molded as a closed circular component sized to fit a given bearing diameter. It may be adapted to fit different sized bearings by removing an appropriately dimensioned circumferential segment, and by bending the remainder of the coolant guard around the axis of the different sized diameter bearing.
A potential difficulty with this type of arrangement is that during service the stiffer mounting flange 36 may exhibit a tendency to pull away from the mounting surface 42 of the seal end plate. Should this occur, the coolant guard's function could be impaired.
In the past, as shown for example in FIG. 2, coolant guards 34' have been reinforced with a metallic structural element 46 which includes a radial flange 48 positioned to resist pulling away from the mounting surface 42 of the seal end plate. However, the radial disposition of the flange 48 limits the ability of the coolant guard to flex about the axis of the bearing and thereby inhibits its adaptability to smaller bearing diameters.